The present invention relates to ophthalmic compositions useful for lubricating eyes to which such compositions are administered. More particularly, the present invention relates to compositions including mixtures of components which are very effective in providing desired eye lubrication without unduly interfering with vision, to methods for making ophthalmic compositions and to methods for lubricating eyes and treating eyes having dry eye syndrome using ophthalmic compositions.
Mammalian eyes, such as human eyes, advantageously are adequately lubricated to provide eye comfort and to more effectively provide good, clear vision, ordinarily, such lubrication is obtained naturally from a tear film, which is formed over the outer, exposed surface of the eye. However, in many instances, this tear film is not present in a sufficient amount to effectively lubricate the eye. A condition known as “dry eye” can result from inadequate lubrication of the eye.
A relatively large number of compositions have been suggested for use in providing eye lubrication. For example, artificial tears, that is materials having chemical compositions which mimic or resemble natural tears, have been used. Such artificial tears often require very frequent use since they are rapidly lost from the eye. In addition, although they wet the eye, their value in lubricating the eye is somewhat less than optimal. Compositions which include specific lubricants have been suggested. For example, a number of materials including carboxy methylcelluloses (CMCs) have been used in eyes. These compositions, which are generally effective, have certain shortcomings. For example, certain low viscosity CMC-containing materials require frequent administration since they are rapidly lost from the eye. In other words, such materials do not adhere to the eye sufficiently to provide effective lubrication without frequent replenishment. High viscosity CMC-containing materials effectively adhere to eyes but are disadvantageously disruptive to clear vision for relatively long periods of time after administration.
There continues to be a need for compositions which are effective to provide lubrication to eyes that can be conveniently used, e.g., administered over acceptable intervals of time, rather than very frequently, and without being unduly disruptive to clear vision.